SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26745230bddce3a1210b751d5b6aff9e9f937e472031eda5505655a57a44b256' 
  AND token = 'mVrwuG41t6/g6Lc7qHWGz2jEKVYnCeZ1QsNIdxYKwK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}